1. Field of the Invention
The present invention relates to a process for producing a liquid ejection head.
2. Description of the Related Art
An ink jet recording head applied to an ink jet recording system generally has an ink flow path, an energy-generating section installed in a part of the ink flow path, and a minute ink ejection orifice to eject an ink. As a process for producing such an ink jet recording head, Japanese Patent Application Laid-Open No. H06-286149 discloses a process in which a mold of an ink flow path is patterned with a photosensitive resin material on a substrate on which an electrothermal conversion element serving as an energy-generating element is formed; a coating resin layer to form the ink flow path on the substrate is applied and formed so as to coat the mold pattern; an ink ejection orifice to communicate with the mold of the ink flow path is formed on the coating resin layer; and then the photosensitive material used for the mold is removed.
The ink jet recording head produced by the above process is a so-called side shooter-type ink jet recording head in which the growth direction of a bubble to be the ejection energy is the same as the ejection direction of an ink. In the side shooter-type ink jet recording head, since an ink supply port passing through the substrate needs to be formed in order to supply the ink to the ink flow path, the ink supply port is formed by sandblast processing in Japanese Patent Application Laid-Open No. H06-286149. Japanese Patent Application Laid-Open No. 2009-119725 discloses mechanical processing using a drill, processing using a light energy such as laser light and a processing method using chemical etching. Further, a method of forming an ink supply port from the back surface of a silicon substrate by a chemical etching (anisotropic etching) using tetramethylammonium hydride (TMAH) is exemplified.
In the case where an ink supply port is formed from the back surface of a substrate by anisotropic etching, in order to protect an ejection-orifice-forming member already formed on the surface of the substrate from erosion by an etchant, a process of coating the ejection-orifice-forming member with a protection film material can be mentioned. Japanese Patent Application Laid-Open No. 2009-119725 discloses a process of using a resin material composed of a cyclized isoprene as a protection film material.